Every spring, the Environmental Working Group (EWG) publishes its Shopper's Guide to Pesticides in Produce, better known as the "Dirty Dozen" and "Clean Fifteen." It ranks the produce most and least likely to carry pesticide residues.
The 2026 edition landed with a finding worth paying attention to. Nearly all Dirty Dozen samples (96%) tested positive for pesticide residues. And for the first time, the report flagged that 63% of those samples contained PFAS pesticides, the so-called "forever chemicals" that don't break down in the environment or in the body.
The simplest answer to that problem is also the most satisfying one - grow your own.
Here are five of the plants worth growing in your own greenhouse every year, why they earn their spot, and how to get the most out of each.
1. Kale
Spinach took the top spot on the 2026 Dirty Dozen list for the second year in a row. Not everyone is a fan of the taste, so kale is the natural alternative. It sits right behind spinach at #2, grouped with collard and mustard greens.
Kale samples have historically tested positive for DCPA, a herbicide banned in Europe since 2009. The EPA finally canceled all U.S. uses of DCPA in August 2024 after the manufacturer turned over data (a decade after being asked) showing that even low exposures could disrupt thyroid hormones during fetal development. That story alone is reason enough to grow your own.
The plant itself is generous. High in antioxidants and vitamins, it works sautéed, in salads, or baked into kale chips. Start it in the greenhouse early and move the plants outdoors once the weather warms - Kale prefers cooler temperatures and tends to bolt in heat.
2. Strawberries
Strawberries sit at #3 on the 2026 list. They've been near the top of the Dirty Dozen for years for the same reason: thin skin, high pest pressure, and a long growing season that invites repeated spraying.
They're also one of the best summer fruits to grow at home. As a plant, they're prolific and forgiving, almost too easy to grow.
Start them in the greenhouse and move them outdoors during the hottest weeks, then bring everbearing varieties back inside in cooler weather to extend the harvest. A tip worth stealing: hang them in baskets inside the greenhouse - they produce just as well, and you free up valuable floor space for everything else.
3. Bell and Hot Peppers
Peppers didn't quite make the Dirty Dozen top 12 in 2026, but EWG called them out specifically, alongside green beans, as items that just missed the cut and ranked high on overall pesticide toxicity. The toxicity factor was added to EWG's methodology in 2025, and peppers are one of the produce items that score worse under the updated ranking than they did under the old one.
They're also expensive at the store, especially the colorful ones, and they get eaten fresh and sautéed.
Peppers are tricky from seed. Soak the seeds, start them indoors where the warmth is controlled, then move the seedlings into the greenhouse as early as the temperatures allow. The extra weeks of head start are what turn a hopeful little plant into something that actually produces by mid-summer.
4. Tomatoes
Tomatoes are off the 2026 Dirty Dozen list, and that's worth being honest about. But they're still a plant most growers wouldn't buy conventional if they could grow them themselves.
Two reasons. The skin is thin and the water content is high, which makes them harder to clean than firmer produce. And the taste gap between a tomato off the vine and a watery supermarket tomato is enormous. Cherry and heirloom varieties are the easiest to snack on through the summer. String up supports to the greenhouse frame as they climb.
This is the one on the list where flavor, not just pesticide load, makes the case.
5. Cucumbers
Cucumbers, like tomatoes, didn't make the 2026 Dirty Dozen top 12, but they sit in a category worth being cautious about anyway. The peel is where most of the fiber and vitamins are, and the peel is also exactly what a pesticide residue sits on.
Better to control what goes on a vegetable that gets eaten skin and all.
There's also the consistency problem with store-bought cucumbers. Too many come home bitter or watery. Growing your own solves that. Tiny cornichons make a great kid-friendly snack item. Trellis them inside the greenhouse to keep the vines off the ground and the fruits clean.
How to Decide What to Grow
If you only have room for a few crops, start with these questions:
- What does your family actually eat? Don't grow what looks good in catalogs. Grow what disappears at the table.
- What costs the most at the grocery store? Berries and colorful peppers usually top the list.
- What has thin skin or an edible peel? Those are the items where residues matter most.
The good news from the research side is that exposure isn't permanent. Studies have linked switching to a diet lower in synthetic pesticides with measurably lower pesticide levels in the body within days. A greenhouse doesn't just give you a longer season. It gives you control over what touches your food before you eat it.
That, more than any single crop on this list, is the reason it earns its place in the garden.
See our polycarbonate greenhouse collection
If you're thinking about growing more of your own food and want to compare greenhouse styles, our team put together a side-by-side comparison of three polycarbonate models for backyard growers. And if you're just getting started, 5 things to know before buying your first greenhouse covers what most first-time buyers wish they'd been told.
Frequently Asked Questions
Does growing your own produce actually reduce pesticide exposure?
Yes. Peer-reviewed studies have linked switching to a diet lower in synthetic pesticides with measurably lower pesticide levels in the body, often within days. Growing your own in a controlled environment like a greenhouse gives you direct control over what's used (and what isn't) on the food you eat.
Which of these five plants is the easiest for a beginner?
Kale and strawberries are the most forgiving. Kale tolerates cool temperatures and uneven watering. Strawberries are prolific and spread on their own. Tomatoes are the next step up. Peppers and cucumbers take more attention to warmth and trellising.
Can I grow these crops year-round in a greenhouse?
It depends on your climate and your greenhouse setup. Kale handles cool greenhouse temperatures well into late fall and early spring. Strawberries, tomatoes, peppers, and cucumbers are warm-season crops. They thrive from spring through fall, and with the right heating and light, some growers extend them further. For practical techniques, see our guide on how to extend your greenhouse growing season.
